JPH07134196A - Reactor monitoring device - Google Patents

Abstract

PURPOSE:To monitor core state substantially in the actual time. CONSTITUTION:This device has a core monitoring parameter arithmetic means for inputting a process data and periodically calculating an power distribution and a maximum local linear power density distribution by the whole core three-dimensional model, a core performance monitoring calculation means 5 for editing the arithmetic result into core monitor information, and a power distribution correcting arithmetic means 10 for calculating the power distribution changed timewise in a short period from this periodically renewed core monitor information by use of a process data of actual time. The device further has a maximum local linear power density correcting arithmetic means 31 for calculating the maximum local linear power density distribution of substantially actual time from this arithmetic result and the core monitor information of the core performance monitoring calculating means 5, a correction data flattening means 32 for avoiding the discontinuity between the arithmetic results of the output distribution correcting arithmetic means 10 and the maximum local linear power density correcting arithmetic means 31 and the core monitor information of the core performance monitoring calculating means 5, and a neutron flux distribution correcting arithmetic means 33 for calculating the substituent value of the process data showing an abnormal value.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a nuclear reactor monitoring system for monitoring the combustion state of a plurality of fuel assemblies installed in a nuclear reactor.

[0002]

2. Description of the Related Art Conventionally, in a plant using a nuclear reactor, for example, a boiling water nuclear power plant (hereinafter referred to as BWR), several hundred fuel assemblies are housed in the nuclear reactor. Between the fuel assemblies, hundreds of control rods for controlling the medieval bundles and sensors for detecting the medieval bundles are inserted.

In this nuclear reactor, each control rod is driven by a hydraulic piston or a motor drive unit to be inserted into or removed from each fuel assembly. Further, the drive device is configured to be operated by the operation of the control rod drive circuit by the switch operation of the operator. The insertion / removal position of each control rod with respect to each fuel assembly is divided into several tens to several hundreds of stages.The neutron flux is reduced as the control rod is inserted into the fuel assembly, and the neutron flux is reduced as the control rod is pulled out. Can be increased.

A coolant (for example, light water in BWR) passing through the reactor is circulated in or outside the reactor in order to extract thermal energy generated during nuclear fission. Multiple recirculation pumps are installed. The coolant recirculation pump is driven by a motor drive unit to change the coolant flow rate, and the motor drive unit is operated by an operator's switch operation. This coolant can increase the neutron flux as the flow rate circulating in each fuel assembly increases and decrease the neutron flux as the flow rate decreases.

On the other hand, each fuel assembly is formed by bundling dozens of fuel rods having a length of about 12 ft. Each fuel rod includes a cladding tube and fuel pellets packed in it (fuel is hardened). ). The neutron flux is directly related to the power density generated by the fuel pellets, and if the power density exceeds a certain value, it may adversely affect the cladding and the fuel pellets. For each assembly, in particular, carefully monitor the power distribution and maximum local line power density distribution of the fuel assembly with the largest power density,
Control rod and coolant recirculation flow must be controlled to ensure that the power density does not exceed a certain value.

As described above, when changing the output of the nuclear reactor, there are two methods of operating the control rod and operating the coolant recirculation flow rate. The output distribution of changes. When the reactor operator performs these operations, it is necessary to monitor the change in the power distribution accompanying the operations.

In order to monitor the power distribution and the maximum local line power density distribution for each fuel assembly, the technology of the process computer has been used to read the neutron flux detector installed in the core. , The core performance calculation system for calculating the power distribution was applied by applying it to the numerical empirical formula calculated in advance, but the neutron flux detector was greatly dependent on the reading of the neutron flux detector. In the case of a failure, accurate core monitoring may not be possible.

Therefore, in recent years, a core operation management system as shown in FIG. 14 has been newly developed. In FIG. 14, process data is input to the plant data input means 3 from each sensor 2 such as a neutron flux detector installed in the nuclear power plant 1, and based on the input process data, the core monitoring parameter calculation means 4 The power distribution in the reactor and the maximum local line power density distribution are calculated as core monitoring parameters. The calculation result of the core monitoring parameter calculation means 4 is edited by the core performance monitoring calculation means 5, converted into display data by the display data creation means 6, and displayed on the display means 7 such as a CRT display. Reference numeral 8 is a parameter setting means for the reactor operator to set an arbitrary parameter corresponding to the process data, and 9 is for calculating a core monitoring parameter based on the parameter set via the parameter setting means 8. It is a core performance prediction calculation means for requesting the core monitoring parameter calculation means 4 and editing the calculation result.

In the core operation management system having this structure, the core monitoring parameter calculation means 4 has a built-in three-dimensional model of the whole core using a physical model such as a neutron diffusion equation. It is possible to calculate the power distribution and maximum local line power density distribution of each fuel assembly in the core with high accuracy without reading. Further, in this core operation management system, by incorporating the whole core three-dimensional model, the control rod position and the coolant recirculation flow rate, which are assumed arbitrarily, are set through the parameter setting means 8 and the set parameters are set according to the set parameters. It is also possible to predict the core condition.

In a nuclear reactor monitoring apparatus using such a core operation management system, the power distribution of each fuel assembly in the core and the maximum local line power density distribution calculation can be performed once due to the problem of the processing capacity of the process computer. Since it takes about 5 minutes, the core monitoring is generally performed once every 10 minutes to 1 hour.

[0011]

However, in such core monitoring once every 10 minutes to 1 hour, it is not always necessary to monitor the core condition immediately after the operation of the control rod and the adjustment of the coolant recirculation flow rate. This is not always possible, and there is a risk of operating the nuclear reactor that adversely affects the fuel rod cladding tube and the fuel pellets as described above.

The present invention has been made to solve such a problem, and constantly calculates the power distribution of each fuel assembly in the core or the maximum local line power density distribution in a relatively short time,
It enables to monitor the core condition almost in real time and confirms the core condition immediately after control rod operation and coolant recirculation flow rate adjustment, while operating the reactor without adversely affecting the fuel rod cladding tube and fuel pellets. It is an object of the present invention to provide a reactor monitoring device capable of performing the above.

[0013]

That is, a reactor monitoring apparatus of the present invention uses a plant data input means for inputting process data from a nuclear power plant, and process data input by this plant data input means for the entire reactor core. Core monitoring parameter calculation means for calculating the power distribution and maximum local line power density distribution in the reactor by a three-dimensional model, and core performance monitoring calculation means for editing core monitoring information using the calculation result of this core monitoring parameter calculation means And the core monitoring information edited by the core performance monitoring calculation means is input, and the process data input to the plant data input means is used to change with the time until the next calculation by the core monitoring parameter calculation means. Output distribution correction calculation means for calculating the output distribution to be output in a short cycle and outputting it as a corrected output distribution; And a display data creation unit for converting the core monitoring information edited by the performance monitoring calculation unit and the corrected output distribution calculated by the output distribution correction calculation unit into display information for displaying on the display unit. To do.

Further, according to the present invention, in the reactor monitoring apparatus having the above-mentioned structure, the core monitoring information edited by the core performance monitoring calculating means is input, and the corrected power distribution calculated by the power distribution correction calculating means is used. , The maximum local line power density distribution that changes with time until the next calculation by the core monitoring parameter calculation means is calculated in a short period, and is output to the display data creation means as the corrected maximum local line power density distribution. It is characterized by further comprising a linear output density correction calculation means.

Further, the present invention is, in the reactor monitoring apparatus having the above structure, the corrected output distribution calculated by the output distribution correction calculating means, and the corrected maximum local line output calculated by the maximum local line power density correction calculating means. The density distribution and the core monitoring information edited by the core performance monitoring calculation means are input, and the output distribution and the maximum local line power density distribution are periodically updated and the corrected output distribution and the corrected maximum local line power density distribution are compared. It is characterized by further comprising a correction data smoothing means for smoothing each discontinuity phenomenon.

Still further, according to the present invention, in the reactor monitoring apparatus having the above-mentioned configuration, the process data used by the core monitoring parameter calculation means for calculation and the latest process data from the plant data input means are input to If there is a faulty detector out of the plurality of neutron flux detectors inserted into the neutron flux detector, the neutron flux distribution correction calculation means for calculating a value to substitute for this and outputting it to the output distribution correction calculation means is further provided. Is characterized by.

Furthermore, according to the present invention, in the reactor monitoring apparatus having the above-mentioned structure, a parameter setting means for inputting an arbitrary parameter in place of the process data from the nuclear power plant, and the parameter setting means are inputted. And a core performance prediction calculation means for causing the core monitoring parameter calculation means to calculate the power distribution and the maximum local line power density distribution with parameters, editing the core prediction information based on this calculation result, and outputting it to the display data creation means. It is characterized by

[0018]

In the above structure, the plant data input means has process data relating to the reactor output, such as local neutron flux count value (hereinafter referred to as LPRM count value), control rod position signal, and coolant recirculation flow rate. Also, process quantities such as recirculation temperature, steam flow rate and steam temperature, feed water flow rate and feed water temperature are input at regular intervals from various sensors installed in the nuclear power plant. The core monitoring parameter calculation means has a built-in three-dimensional core model that uses physical models such as the neutron diffusion equation, and based on the input process data, the power distribution and maximum local line output for each fuel assembly in the core The density distribution is calculated with high accuracy at a rate of once every 10 minutes to 1 hour. The core performance monitoring calculation means inputs the power distribution calculated by the core monitoring parameter calculation means, the maximum local line power density distribution and the process data used for the calculation, and edits the core monitoring information required by the reactor operator. .

The power distribution correction calculation means inputs the power distribution and process data at the time of calculation of the core monitoring information periodically updated from the core performance monitoring calculation means, and the latest data from the plant data input means. Data is input, the output distribution input from the core performance monitoring calculation means is corrected using the latest process data, and the corrected output distribution that changes from moment to moment is calculated. The display data creation means inputs the output distribution updated periodically from the core performance monitoring calculation means in response to a display request from the reactor operator, and the corrected output distribution updated in a short cycle from the output distribution correction calculation means. Is input, display screen data is created, and an output distribution curve at an arbitrary fuel assembly position is displayed on a display means such as a CRT display.

As described above, the output distribution updated as a result of the core performance monitoring calculation means, which is updated in a relatively long period, and the corrected output distribution, which is a calculation result of the output distribution correction calculation means, which changes from moment to moment. By displaying at the same time,
Reactor operators can monitor the power distribution in almost real time, and even during control rod operation and coolant recirculation flow rate adjustment during operation of the core performance monitoring calculation means, operation and operation can be performed. The output distribution immediately after can be monitored in comparison with that before operation.

Further, the maximum local line power density correction calculation means inputs the maximum local line power density distribution and the power distribution in the core monitoring information which is periodically updated from the power distribution correction calculation means, and the power distribution correction is carried out. The corrected output distribution that changes from moment to moment is input from the calculation means, and the corrected local maximum power distribution is corrected using the corrected output distribution to obtain the corrected maximum local power distribution that changes from moment to moment. It is something that is calculated.

In the case where this means is further added, the display data creating means produces the power distribution and the maximum local line power density distribution which are periodically updated from the core performance monitoring calculation means in response to a display request from the reactor operator. In addition to inputting, input the corrected output distribution and the corrected maximum local line output density distribution that are updated in a short period from the output distribution correction calculating unit and the maximum local line output density correction calculating unit, create display screen data, and arbitrarily The power distribution curve of the fuel assembly position and the maximum local line power density distribution curve are displayed on a display means such as a CRT display.

As a result, the reactor operator can constantly monitor the time variation of the maximum local line power density distribution together with the power distribution, and control rod operation and operation while the calculation result is updated by the core performance monitoring calculation means. Even when the coolant recirculation flow rate is adjusted, the power distribution and the maximum local line power density distribution during or immediately after the operation can be monitored in comparison with those before the operation.

Further, the correction data smoothing means inputs the power distribution and the maximum local line power density distribution in the core information regularly updated from the core performance monitoring calculation means, and occasionally outputs from the power distribution correction calculation means. The corrected output distribution that changes momentarily, and the corrected maximum local line power density distribution that changes momentarily from the maximum local line power density correction means are input, and the contents of the core monitoring information are updated periodically. The discontinuity between the generated power distribution after correction and the corrected maximum local line power density distribution with the core monitoring information is eliminated, and the correction calculation for smoothing is performed so that each becomes a continuous value.

By further providing this correction data smoothing means, the output distribution and the maximum local line output density distribution which are regularly updated are smoothly continuous with the corrected output distribution and the corrected maximum local line output density. The distribution can be obtained.

Further, the neutron flux distribution correction calculation means inputs the process data at the time of calculation from the core performance monitoring calculation means and the latest process data from the plant data input means, and has an LPRM count value indicating an abnormality. In this case, the neutron flux value serving as an alternative value is calculated and output to the output distribution correction calculating means.

By providing the neutron flux distribution correction calculation means, a failure occurs in a plurality of local neutron flux detectors (hereinafter referred to as LPRMs) installed in the nuclear reactor, and the count value of the LPRMs is calculated. Even when it cannot be used, the substitute value can be obtained with high accuracy, so that the fuel assembly in the vicinity of the failed LPRM can be monitored.

Further, in the configuration provided with the core performance prediction calculation means, the reactor operator predicts the core performance by inputting a parameter relating to an arbitrary reactor output through the parameter setting means which can be realized by a keyboard or the like. The calculation means activates the core monitoring parameter calculation means with the input and set parameters, calculates the power distribution and the maximum local line power density distribution based on this parameter, and edits and displays the core prediction information using the calculation result. It is displayed on the display means via the data creating means.

As a result, the display means displays the output distribution / maximum local line power density distribution which is regularly updated and the corrected output distribution / corrected maximum local line power density distribution which changes from moment to moment. , The predicted core status after completion of power change operation is displayed as needed, so that the reactor operators can easily understand the changes in the core status before, during, and after the operation. It can be used for safe operation of the furnace.

[0030]

Embodiments of the present invention will be described below with reference to the drawings. The same parts as those of the conventional example are designated by the same reference numerals.

FIG. 1 is a block diagram showing a first embodiment of the nuclear reactor monitoring apparatus of the present invention. In this embodiment, an output distribution correction calculating means 10 is added to the conventional example shown in FIG. .

In this structure, various sensors are installed in the nuclear power plant 1 including a nuclear reactor which houses a plurality of fuel assemblies therein. These are various sensors installed to measure the amount of processes involved.

Referring to FIG. 2, representative examples of the various sensors 2 in the BWR are as follows. The various sensors 2 installed to measure the process amount related to the reactor output are inside the reactor 11. Detects the vertical position of the LPRM 13 that is inserted between the plurality of fuel assemblies 12 that are housed, and the control rod 15 that is driven by the control rod drive device 14 and that is inserted into and removed from the plurality of fuel assemblies 12. A control rod position detector 16 and a recirculation pump 17 for extracting thermal energy generated by fission of fuel
The recirculation flow rate detector 18 and the recirculation temperature detector 19, which measure the recirculation flow rate and the recirculation temperature of the coolant (light water in this case) circulating in the unit 1, and are converted by the heat energy removed by the coolant. A steam flow detector 20 and a steam temperature detector 21, which respectively measure the flow rate and temperature of the main steam taken out of the reactor 11, and the reactor 11 for replenishing the in-reactor coolant that decreases as the steam is taken out. There are a feed water flow rate detector 22 and a feed water temperature detector 23 that measure the flow rate and temperature of the feed water supplied to the inside.

In addition, the coolant purification flow rate (not shown) may vary slightly depending on the applied nuclear power plant.
And its temperature (not shown) or control rod driving water flow rate (not shown) and its temperature (not shown).

The plant data input means 3 is realized by a signal adjusting device provided as a peripheral device of the process computer, and inputs the process data from the sensor 2 into the process computer as a value that changes from moment to moment.

The core monitoring parameter calculation means 4 has a built-in three-dimensional model of the whole core using a physical model such as a neutron diffusion equation. Basically, the core monitoring parameter calculation means 4 is highly accurate even if there is no LPRM measurement value, and each fuel in the core is highly accurate. The output distribution and maximum local line power density distribution for each aggregate can be calculated. In addition, the calculation procedure is stored in advance in the process computer,
Although it depends on the processing capacity of the process computer, since one calculation takes about 1 to 5 minutes, the periodic execution synchronization is limited to once every 10 minutes to 1 hour.

The core monitoring parameter calculation means 4 is activated by a calculation request signal sent from the core performance monitoring calculation means 5 or the core performance prediction calculation means 9, and executes calculation at that timing. The parameters that need to be set externally when executing the calculation are the plant data input means 3 in response to the calculation request from the core performance monitoring calculation means 5.
The parameter setting means 8 inputs the calculation request from the core performance prediction calculation means 9.

Normally, the core monitoring parameter calculation means 4 is
By the calculation request signal which is periodically sent from the core performance monitoring calculation means 5 at a time interval of about once every 10 minutes to 1 hour,
Process data relating to the reactor power at that time is input from the plant data input means 3 as a calculation parameter, and the power distribution and the maximum local line power density distribution are calculated.

Further, when the reactor operator uses the parameter setting means 8 which can be realized by a keyboard or the like, and inputs a calculation parameter in place of the process data relating to the reactor output to the process computer, the core performance prediction calculation is performed. The calculation request signal from the means 9 is the core monitoring parameter calculation means 4
Then, the core monitoring parameter calculation means 4 calculates the power distribution and the maximum local line power density distribution based on the calculation parameters given from the parameter setting means 8 via the core performance prediction calculation means 9.

The core performance monitoring calculation means 5 is from 10 minutes to 1
A calculation request signal is periodically generated to the core monitoring parameter calculation means 4 at a time interval of about once per hour, and in response to this, the core monitoring parameter calculation means 4 inputs from the plant data input means 3 at that time. Input the power distribution and maximum local line power density distribution calculated based on the process data related to the reactor power, and edit the core monitoring information required by the reactor operator.

The power distribution correction calculation means 10 is used for the power distribution and calculation from the core monitoring information which is periodically updated by the core performance monitoring calculation means 5 at a time interval of about once every 10 minutes to 1 hour. Parameter (process data at the time of calculation) is input, and process data that changes from moment to moment is input from the plant data input means 3,
The output distribution calculated by the core monitoring parameter calculation means 4 is corrected, and the corrected output distribution that changes momentarily is calculated.

The core performance prediction calculation means 9 is concerned with the reactor output supplied by the reactor operator from the parameter setting means 8 represented by a keyboard or the like to the core monitoring parameter calculation means 4 by the plant data input means 3. By inputting a parameter having the same meaning as the process data (hereinafter referred to as a parameter set by the reactor operator), the parameter set by the reactor operator to the core monitoring parameter calculation means 4 based on this input. A calculation request signal is sent together therewith, and in response thereto, the core monitoring parameter calculation means 4 calculates the power distribution in the reactor and the maximum local line power density distribution calculated based on the parameters set by the reactor operator, and the core has a constant output. Enter the parameter that indicates whether the reactor can be operated in To edit.

The display data creating means 6 receives the power distribution especially in the core monitoring information from the core performance monitoring calculating means 5 and the power distribution from the core prediction information in particular from the core performance prediction calculating means 9, The corrected output distribution that changes from moment to moment is input from the output distribution correction calculation means 10, and further,
By inputting coordinate data of an arbitrary fuel assembly 12 (FIG. 2) desired by the reactor operator from the parameter setting means 8 represented by a keyboard which can be prepared as a peripheral device of the process computer, it is shown in FIG. Display screen data for displaying such a display screen on the display means 7 represented by a CRT display that can be prepared as a peripheral device of a process computer is created. For example, the arrangement position of the fuel assembly 12 in the core is displayed on the left side of the screen by the X coordinate (horizontal axis) and the Y coordinate (vertical axis), and the color of the fuel assembly 12a at the coordinates input by the reactor operator. Is displayed in a color different from that of the other fuel assemblies 12b, and the output distribution in the axial direction (Z direction) of the fuel assembly 12a at the coordinates is displayed in a graph on the right side of the screen. At that time, the power distribution curve (dotted line) regularly updated by the core performance monitoring calculation means 5 and the core performance prediction calculation means 9
And the output distribution curve (solid line) sent from the output distribution correction calculation means 10 that changes from moment to moment are displayed in a distinguishable manner.

Next, the operation of the output distribution correction calculating means 10 will be described in more detail.

In the description of the embodiment of the present invention, the virtual core of the nuclear reactor shown in FIGS. 4 to 6 is used. FIG. 4 is a plan view of the virtual core indicated by XY coordinates, and FIG. 5 is a three-dimensional schematic view of the virtual core illustrating Z coordinate positions. Further, FIG. 6 is a partially enlarged view of the virtual core of FIG. 5 and shows the Z-direction installation position of the LPRM inserted between the plurality of fuel assemblies 12.

In this virtual core, the number of fuel assemblies 12 is 1
There are 56 bodies, and a serial number L of 1 to 156 is assigned to each of them as shown in FIG. Further, the integrated fuel assembly 12 is divided into 24 in the axial direction (Z direction) as shown in FIG. 5 (the length of each of the 24 divisions is called a node), and its output distribution and maximum local line output density are shown. Is being calculated. This is a serial number K from 1 to 24 from bottom to top
Turn on.

Further, in the virtual core of FIG. 4, the number of control rods 15 is 37, and each of the control rods 15 is surrounded by 4 control rods 15.
An LPRM 13 is inserted in the center of the fuel assembly 12 of the body. Here, the XY in which the LPRM 13 is inserted
The position on the coordinates is called the LPRM string 13 '. There are 32 LPRM strings 13 ', and each LPRM string 13' has an LPRM string 13 'as shown in FIG.
4 are inserted in the axial direction (Z direction). This LPR
A serial number 1 to 4 is assigned to M13 from the bottom in the Z direction.

FIG. 7 is a flow chart showing the operation of the output distribution correction calculating means 10. As shown in this flowchart, the power distribution correction calculating means 10 first inputs the power distribution in the core monitoring information at a constant cycle from the core performance monitoring calculating means 5 (step 100). In the virtual core of FIG. 4, 156 (body) × 24 (node) = 3744 at a time
Input the output distribution data of 8 (nodes). This is compared with the output distribution stored in a storage device represented by a memory or the like (step 101), and if they do not match, it is determined that the output distribution has been updated by the core performance monitoring calculation means 5,
This output distribution is stored in the storage device (step 10).
2).

Next, at step 103, the average value P _av (K) of the outputs at the same height in the axial direction (Z direction) is set for each set of four fuel assemblies 12 around the LPRM string 13 '. (K = 1 to 24) is calculated.

For example, focusing on the set of fuel assemblies 12 of L = 9, 10, 19, 20 surrounding the LPRM string 13 ', the average value P _av (K) of the output is given by the following equation.

[ _Formula 1] P _av (K) = (P (9, K) + P (10, K) + P (1
9, K) + P (20, K)) / 4 However, calculation is performed according to K = 1 to 24, and then each fuel assembly (L = 9,10,
19, 20) to the average value P _av (K) of this output CP (L, K)

## EQU2 ## CP (L, K) = P (L, K) / P _av (K) where L = 9, 10, 19, 20 and K = 1 to 24 are calculated.

Next, in step 104, the LPRM count value RP (N) (N = 1 to 4) is input from the parameters used for the calculation by the core performance monitoring calculation means 5. The number is 32 (pieces) × 4 (pieces) = 128 (pieces).

In step 105, the relationship C (N) between P _av (K) (K = 1 to 24) calculated in step 103 and RP (N) (N = 1 to 4) input in step 104 is expressed by
The following formula

## _EQU3 ## C (N) = LP _av (N) / RP (N) where N = 1 to 4 LP _av (1) = (P _av (3) + P _av (4)) / 2 LP _av (2 ) = (P _av (9) + P _av (10) / 2 LP _av (3) = (P _av (15) + P _av (16)) / 2 LP _av (4) = (P _av (21) + P _av ( 22)) / 2 according to its axial height at the same height.

At step 106, the LPRM count value RP '(N) at the current time is input from the plant data input means 3, and at step 17, the current time is calculated based on the C (N) calculated at step 105. The output distribution average value LP ′ _av (N) at the LPRM position is calculated by the following equation.

## EQU4 ## LP ' _av (N) = C (N) .RP' (N) where N = 1 to 4 are used for the calculation. Then LP ' _av (N) and LP
_av (N) difference DRP (N)

## EQU5 ## DRP (N) = LP ' _av (N) -LP _av (N) However, N = 1 to 4 is obtained. Further, consider a quintic equation such that the value at a certain position N of the LPRM13 becomes DRP (N) and the value of the extrapolation 0 point becomes 0, and the function value DR for each node position in the axial direction is calculated by the quintic equation. (K) (K = 1 to 2
4) is asked. From this DR (K), the average value P ′ _av (K) of the axial power distribution at the current time is

## _EQU6 ## _P'av (K) = _Pav (K) + DR (K) However, K = 1 to 24 holds.

Next, at step 108, 4 values around the LPRM string 13 'are calculated from the average value _P'av (K) of the axial power distribution at the present time for each LPRM string 13'.
For each body fuel assembly, the axial output distribution (that is, the corrected output distribution) P ′ (L, K) at the current time is calculated.

For example, L = 9, 10, 1 focused on the above.
Regarding the 9 and 20 fuel assemblies,

## EQU00007 ## P '(L, K) = CP (L, K) .P'
_av (K) However, it is calculated | required by K = 1-24 L = 9,10,19,20.

If the output distribution input in step 101 and the output distribution in the storage device match, it is determined that the output distribution has not been updated by the core performance monitoring calculation means 5, and step 106 is executed. The corrected output distribution is calculated by the following processing.

As is clear from the above description, according to the present embodiment, it is basically assumed that the output distribution is proportional to the LPRM count value, and after the correction is performed in a relatively short time by the method as simple as possible. By providing the power distribution correction calculation means 10 capable of calculating the power distribution, the power distribution in the axial direction of each fuel assembly can be monitored in real time, and the safety of the reactor operation can be improved. You can Figure 8
A second embodiment of the reactor monitoring system of the present invention is shown, which has a configuration in which maximum local line power density correction calculation means 31 is added to the first embodiment shown in FIG. It should be noted that duplicated description of portions common to the first embodiment will be omitted.

In this configuration, the maximum local line power density correction calculation means 31 is the maximum of the core monitoring information which is regularly updated from the core performance monitoring calculation means 5 at a time interval of about once every 10 minutes to 1 hour. The local line output density distribution and the output distribution are input, and the corrected output distribution that changes from moment to moment is input from the output distribution correction calculation means 10, and the maximum local line output density distribution is subjected to the output distribution and the corrected output distribution. Is used to calculate the corrected maximum local line power density distribution that changes from moment to moment.

In addition to the inputs shown in the first embodiment, the display data creating means 6 inputs the maximum local line power density distribution in the core monitoring information from the core performance monitoring calculating means 5 to calculate the core performance prediction. As shown in FIG. 9, by inputting the maximum local line power density distribution in the core prediction information from the means 9 and further inputting the corrected maximum local line power density distribution from the maximum local line power density correction calculating means 31. Display screen data for displaying the screen on the display means 7 is created.

Next, the operation of the maximum local line power density correction calculation means 31 will be described in more detail with reference to the flow chart shown in FIG.

First, the power distribution and the maximum local line power distribution in the core monitoring information are input from the core performance monitoring / calculating means 5 in a constant cycle (step 200), and this is stored in a storage device represented by a memory or the like. (Step 201), and if different, the input output distribution and maximum local line output distribution are stored (step 202).

Next, the newly stored output distribution P (L,
K) (L = 1 to 156, K = 1 to 24) and the maximum local line power density distribution PD (L, K) ratio CPD (L, K)

[Equation 8] CPD (L, K) = PD (L, K) / P (L,
K) However, L = 1 to 156 and K = 1 to 24 are calculated (step 203).

Then, the corrected output distribution P '(L, K) (L = 1 to 156, K = 1) is output from the output distribution correction calculation means 10.
~ 24) is input (step 204).

From the corrected output distribution P '(L, K) and the CPD (L, K) calculated in step 203, the corrected maximum local line output density distribution PD' (L, K) is calculated as follows.

## EQU9 ## PD '(L, K) = CPD (L, K) .P' (L, K) where L = 1 to 156 K = 1 to 24 is calculated (step 205).

If the distribution data in the storage device and the distribution data input from the core performance monitoring calculation means 5 are the same in step 201, the process proceeds to step 204.

As is apparent from the above description, according to this embodiment, in addition to the output distribution correction calculating means 10, basically, the ratio between the maximum local line output density distribution and the output distribution does not change. In addition, by providing the maximum local line power density correction calculation means 31 for performing the calculation of the corrected maximum local line power density distribution in a relatively short time by the method as simplified as possible, the output in the axial direction for each fuel assembly is provided. The distribution and the maximum local line power density distribution can be monitored in real time, and the safety of reactor operation can be improved.

FIG. 11 shows a third embodiment of the reactor monitoring system of the present invention.
An example is shown, and a correction data smoothing means 32 is further provided in the configuration of the second example.

In this structure, the operation of each means other than the correction data smoothing means 32 is almost the same as that of the second embodiment, and the duplicated description will be omitted.

The correction data smoothing means 32 inputs the output distribution of the core information periodically updated from the core performance monitoring calculation means 5 at time intervals of about 10 minutes to 1 hour, and outputs the output distribution correction calculation means 10 By inputting the corrected output distribution that changes from moment to moment, and further inputting the corrected maximum local line power density distribution that changes from moment to moment from the maximum local line power density correction means 31, a time of about 10 minutes to 1 hour. Smoothing that eliminates the discontinuities in the corrected power distribution and the corrected maximum local line power density distribution that occur each time the contents of core monitoring information are updated at regular intervals, and creates a continuous value Correction calculation for.

The display data creating means 6 has the corrected output distribution from the output distribution correction calculating means 10 and the corrected maximum local line output density correcting distribution 31 from the maximum local line output density correction calculating means 31, which have been input in the second embodiment. Instead, the corrected output distribution and the corrected maximum local line output density distribution subjected to the smoothing processing are input from the correction data smoothing means 32 to create display screen data.

Further, the operation of the correction data smoothing means 32 will be described in more detail with reference to the flowchart of FIG.

First, smoothing correction coefficients PE, PF, PD
E, PDF

[Equation 10] PE (L, K) = 1 PF (L, K) = 0 PDE (L, K) = 1 PDF (L, K) = 0 However, L = 1 to 156 K = 1 to 24 and reset The previous input values P ′ _o , PD ′ _o
Is reset to 0 (step 300), particularly the power distribution in the core monitoring information is input from the core performance monitoring calculation means 5 (step 301), and the output distribution is stored in a storage device represented by a memory or the like. (Step 30
2) If they are not the same, they are updated and stored in the storage device (step 303).

Next, if it is determined in step 304 that the previous input values P ′ _o and PD ′ _o are in the reset state, step 30
5, the corrected output distribution P ′ (L, K) (L = 1 to 156, K = 1 to 24) is input from the output distribution correction calculation means 10, and the maximum local line output density correction calculation means 31 is input. The corrected maximum local line output density distribution PD ′ (L, K) is input.

The smoothed correction coefficients PE, PF, PDE, and PDE (L, K) and the corrected maximum local line power density distribution PD '(L, K) that have been input are respectively smoothed and corrected.
Correction for smoothing is performed by PDF, and smoothed correction output distribution P ″ (L, K) and smoothed maximum local line output density distribution PD ″ (L, K)

[Equation 11] P ″ (L, K) = P ′ (L, K) · PE
(L, K) + PF (L, K) PD ″ (L, K) = PD ′ (L, K) · PDE (L,
K) + PDF (L, K) However, L = 1 to 156 and K = 1 to 24 are calculated (step 306).

Then, the corrected output distribution P ′ input this time
(L, K) and corrected maximum local line power density distribution PD '
(L, K) is the previous input value _P'o (L, K), PD '
After setting to _o (L, K) (step 307), the process returns to step 301 and the power distribution is input from the core performance monitoring calculation means 5.

If the input output distribution is the same as the data stored in the storage device, the process proceeds to step 308, where the smoothing correction coefficients PE, PF, PDE, and PDF are

[Equation 12] PE (L, K) = PE (L, K) · ΔPE
(L, K) PF (L, K) = MAX (PF (L, K) -ΔPF
(L, K), 0) PDE (L, K) = PDE (L, K) · ΔPDE (L,
K) PDF (L, K) = MAX (PDF (L, K) -ΔPD
F (L, K), 0) However, L = 1 to 156 K = 1 to 24 ΔPE, ΔPF, ΔPDE, ΔPDF; after updating with constants determined in the design stage or the test operation stage of the plant, the step The processes after 305 are repeated.

If the output distribution input in step 301 has been updated, the process proceeds to step 309 via steps 303 and 304, and the smoothing correction coefficient PE,
PF, PDE, PDF are

## EQU13 ## PE (L, K) = 1 PF (L, K) = MAX (P ' _o (L, K) -P'
(L, K), 0) PDE (L, K) = 1 PDF (L, K) = MAX (PD ' _o (L, K) -P
D '(L, K), 0) However, after calibrating according to L = 1 to 156 and K = 1 to 24, the processes of step 305 and thereafter are performed.

As is clear from the above description, since the present embodiment is provided with the correction data smoothing means 32, the control rods in the output distribution correction calculating means 10 and the maximum local line power density correction calculating means 31 are controlled. It is possible to compensate the error due to the rough calculation that does not consider the influences of the drawing pattern, the coolant recirculation flow rate, and the burnup of the fuel, and it is possible to further improve the reliability of core monitoring.

FIG. 13 shows a reactor monitoring system according to a fourth embodiment of the present invention.
An example is shown in which the neutron flux distribution correction calculation means 33 is provided in the configuration of the third example.

In this configuration, the neutron flux distribution correction calculation means 33 is from the core performance monitoring calculation means 5 to 10 minutes to 1 minute.
Process data relating to the reactor power in the core monitoring information that is regularly updated at time intervals of about time, and process data that changes from moment to moment are input from the plant data input means 3, and among the plurality of LPRMs 13. LP
For those for which the RM count value cannot be used, a neutron flux that is an alternative value to this is calculated based on inputs from the core performance monitoring calculation means 5 and the plant data input means 3.

The operation of the neutron flux distribution correction calculating means 33 will be described in more detail with reference to the flowchart of FIG.

First, the neutron flux distribution correction calculation means 33
The LPRM count value RP (N) (N = 1 to 4) is inputted from the process data relating to the reactor output by the core performance monitoring calculation means 5 at a constant cycle (step 40).
0). It is determined whether or not this LPRM count value RP (N) is stored in a storage device represented by a memory or the like (step 401). If not stored, the LPRM count value RP (N) input to the storage device is determined. ) Is stored (step 402). Then, this LPRM count value RP (N)
If there is an abnormal value (for example, 0 or a value close to 0) in the list (step 403), the alternative value is searched for as one of the following (1) to (3). Method and output to the output distribution correction calculation means 10 (step 4).
04).

Here, the LPRM count value RP (N) is data of arbitrary coordinates in the XY coordinate system of FIG.
It will be described as (X, Y, N).

(1) When any of the RPs (12, 13, N) fails, the RPs (16, 0) existing in the vicinity of the RP (12, 13, N)
9, N), RP (16, 17, N), RP (08, 0)
9, N), RP (08, 17, N) at the same height 4
Determined by interpolation from the readings of one LPRM count.

(2) When any one of RP (12,05, N) fails, RP (08,0) existing in the vicinity
9, N), RP (16,09, N) at the same height 2
It is determined by an extrapolation method in which one LPRM count and the extrapolation 0 point are set to 0.

(3) When any of the RPs (08, 05, N) fails, the RPs (12, 0) existing in the vicinity of them.
(9, N) and one extrapolation point at the same height is set to 0, and the extrapolation method is used.

By any of the above methods, the alternative value calculation of LPRMs at all positions in the core can be performed.

The LPR input in step 401 is input.
If the M count value RP (N) is already stored, or if there is no abnormal value in the LPRM count value RP (N) in step 403, the LPRM substitute value calculation in step 404 is not performed, and the direct step is performed. Proceed to 405.

In step 405, the LPRM count value RP '(N) is selected from the process data at the present time (latest) that changes from moment to moment from the plant data input means 3.
Enter. Then, in step 406, the LPRM count value RP ′ (N) is searched for an abnormal value (for example, 0 or a value close to 0), and if there is, it proceeds to step 407 to substitute it. The value is calculated similarly to step 404 and output to the output distribution correction calculation means 10.
If there is no abnormal value in the LPRM count value RP '(N), the process returns to step 400.

As is clear from the above description, according to the present embodiment, the substitute value of the count value of the faulty LPRM is calculated from the normal count value of the LPRMs arranged around, and the output distribution is corrected. By providing the neutron flux distribution correction operation means 33 for outputting to the operation means 10, even when a failure occurs in the LPRM, the influence on the operation result of the neutron flux distribution correction operation means 33 can be minimized, and the reliability can be improved. High real-time monitoring information can be obtained.

The display screen is not limited to the display screen described in the above embodiment, and the calculated output distribution data or maximum local line output density distribution data may be used to create a display screen for plotting this on the time axis. You can also

[0092]

As described above, according to the present invention, the time of the core monitoring data is corrected by the correction based on the core monitoring data such as the highly accurate power distribution which is regularly calculated according to the whole core three-dimensional model. By calculating the change, it becomes possible to obtain the core monitoring information in substantially real time, and the operation of the reactor can be performed more smoothly and more safely and reliably while complying with the restriction on the fuel assembly.

[Brief description of drawings]

FIG. 1 is a block diagram showing a reactor monitoring system according to a first embodiment of the present invention.

FIG. 2 is a schematic view showing a sensor relating to a reactor output installed in a boiling water reactor type nuclear power plant.

FIG. 3 is a diagram showing an example of a display screen of the first embodiment.

FIG. 4 is a plan view showing a configuration of a virtual core of a nuclear reactor.

FIG. 5 is a schematic diagram showing a virtual core of a nuclear reactor in three dimensions.

FIG. 6 is a schematic view showing an axial installation position of the LPRM.

FIG. 7 is a flowchart showing the operation of the output distribution correction calculating means according to the present invention.

FIG. 8 is a block diagram showing a reactor monitoring system according to a second embodiment of the present invention.

FIG. 9 is a diagram showing an example of a display screen of the second embodiment.

FIG. 10 is a flowchart showing the operation of the maximum local line power density distribution correction calculation means according to the present invention.

FIG. 11 is a block diagram showing a reactor monitoring system according to a third embodiment of the present invention.

FIG. 12 is a flowchart showing an operation of the correction data smoothing means according to the present invention.

FIG. 13 is a block diagram showing a reactor monitoring system according to a fourth embodiment of the present invention.

FIG. 14 is a flowchart showing the operation of the neutron flux distribution correcting means according to the present invention.

FIG. 15 is a block diagram showing a conventional example of a reactor monitoring device.

[Explanation of symbols]

 5 ... Core performance monitoring calculation means 9 ... Core performance prediction calculation means 10 ... Output distribution correction calculation means 12 ... Fuel assembly 13 ... LPRM 13 '... LPRM string 14 ... Control Rod drive 15 Control rod 16 Control rod position detector 17 Recirculation pump 31 Maximum local line output density correction calculation means 32 ... Correction data smoothing means 33 ... Neutron flux distribution correction calculation means

Claims (5)

[Claims] 1. A plant data input means for inputting process data from a nuclear power plant, and an output distribution and maximum local line power density in a reactor by a whole core three-dimensional model using the process data input by the plant data input means. The core monitoring parameter calculation means for calculating the distribution, the core performance monitoring calculation means for editing the core monitoring information by using the calculation result of the core monitoring parameter calculation means, and the core monitoring information edited by the core performance monitoring calculation means. By using the process data input to the plant data input means, the output distribution that changes with time until the next calculation by the core monitoring parameter calculation means is calculated in a short cycle, and the corrected output distribution is calculated. And a core monitoring information edited by the core performance monitoring calculating means. ,
And a display data creating means for converting the corrected output distribution calculated by the output distribution correction calculating means into display information for displaying on the display means. 2. The reactor monitoring apparatus according to claim 1, wherein the core monitoring information edited by the core performance monitoring calculation means is input, and the corrected power distribution calculated by the power distribution correction calculation means is used, The maximum local line power density distribution that changes with the time until the next calculation by the core monitoring parameter calculation unit is calculated in a short cycle, and the maximum local line power density distribution after correction is output to the display data creation unit as the maximum. A reactor monitoring apparatus further comprising a local line power density correction calculation means. 3. The reactor monitoring apparatus according to claim 2, wherein the corrected output distribution calculated by the output distribution correction calculation means, and the corrected maximum local line output calculated by the maximum local line power density correction calculation means. The power distribution and the maximum local line after the density distribution and the core monitoring information edited by the core performance monitoring calculation means are input, and the power distribution and the maximum local line after the power density distribution that are periodically updated are corrected. A reactor monitoring apparatus further comprising correction data smoothing means for smoothing discontinuous phenomena in power density distribution. 4. The reactor monitoring device according to claim 1, wherein the process data used by the core monitoring parameter calculation means for calculation and the latest process data from the plant data input means are stored. Input,
If there is a failed detector among the plurality of neutron flux detectors inserted in the reactor, a neutron flux distribution correction calculation means for calculating a value to substitute for this and outputting it to the output distribution correction calculation means A nuclear reactor monitoring device further comprising: 5. The reactor monitoring apparatus according to claim 1, further comprising a parameter setting unit for inputting an arbitrary parameter in place of the process data from the nuclear power plant, and the parameter setting unit. The core performance of causing the core monitoring parameter calculation means to calculate the power distribution and the maximum local line power density distribution with the parameters input via the core, and editing the core prediction information based on the calculation result and outputting to the display data creating means. A nuclear reactor monitoring device comprising: a prediction calculation means.